Extracting data from responses in Postman - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to extract the value of 'token' from the JSON response.

Postman

let token = pm.response.json().[1];

Drag options to blanks, or click blank then click option'

Atoken

Bstatus

Cheaders

Dbody

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to access 'token' directly from pm.response without parsing JSON.

Using incorrect property names like 'status' or 'headers'.

The pm.response.json() method parses the response body as JSON. To get the 'token' value, use pm.response.json().token.

2fill in blank

medium

Complete the code to check if the response status code is 200.

Postman

pm.test('Status code is 200', function () { pm.response.to.have.status([1]); });

Drag options to blanks, or click blank then click option'

A404

B201

C200

D500

Attempts:

3 left

💡 Hint

Common Mistakes

Using 404 which means 'Not Found'.

Using 201 which means 'Created' but not the expected here.

The status code 200 means the request was successful. We check it using pm.response.to.have.status(200).

3fill in blank

hard

Fix the error in the code to correctly extract the 'userId' from the JSON response.

Postman

let userId = pm.response.json()[1];

Drag options to blanks, or click blank then click option'

A['userId']

B.userId

C.userId()

DuserId

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses like a function call.

Trying to access property without dot or brackets.

To access a property in a JavaScript object, use dot notation without parentheses: .userId.

4fill in blank

hard

Fill both blanks to extract the 'email' from the first user in the 'users' array in the response.

Postman

let email = pm.response.json().[1][[2]].email;

Drag options to blanks, or click blank then click option'

Ausers

B0

C1

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'data' instead of 'users' as the array name.

Using index 1 which is the second user.

The response has a 'users' array. To get the first user's email, access users[0].email.

5fill in blank

hard

Fill all three blanks to create a test that checks if the response JSON has a 'success' property set to true.

Postman

pm.test('Response has success true', function () { pm.expect(pm.response.json().[1]).to.eql([2]); pm.expect(typeof pm.response.json().[3]).to.equal('boolean'); });

Drag options to blanks, or click blank then click option'

Asuccess

Btrue

Dstatus

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'status' instead of 'success' property.

Using string 'true' instead of boolean true.

We check the 'success' property equals true and that its type is boolean. Both blanks 1 and 3 refer to 'success'.

Practice

1. What is the primary purpose of extracting data from API responses in Postman?

easy

A. To reuse data in subsequent API requests

B. To change the API endpoint URL

C. To modify the request headers

D. To delete the response data

Solution

1. Step 1: Understand the role of data extraction

   Extracting data allows you to capture values from one response to use later.

2. Step 2: Connect API requests using extracted data

   This helps chain requests by passing data like tokens or IDs forward.

3. Final Answer:

   To reuse data in subsequent API requests -> Option A

4. Quick Check:

   Extract data = reuse in next requests [OK]

Hint: Extract data to pass info between requests [OK]

Common Mistakes:

• Thinking extraction changes the URL
• Confusing extraction with header modification
• Believing extraction deletes data

2. Which Postman script correctly extracts the value of userId from a JSON response and saves it as an environment variable?

easy

A. let data = pm.response.json(); pm.environment.set('userId', data.userId);

B. pm.response.set('userId', pm.response.json().userId);

C. pm.environment.get('userId', pm.response.json().userId);

D. let userId = pm.response.set('userId');

Solution

1. Step 1: Use pm.response.json() to parse JSON

   This method converts the response body into a JavaScript object.

2. Step 2: Use pm.environment.set() to save variable

   Set the environment variable 'userId' with the extracted value.

3. Final Answer:

   let data = pm.response.json(); pm.environment.set('userId', data.userId); -> Option A

4. Quick Check:

   Parse JSON + set env variable = let data = pm.response.json(); pm.environment.set('userId', data.userId); [OK]

Hint: Use pm.response.json() then pm.environment.set() [OK]

Common Mistakes:

• Using pm.response.set() which doesn't exist
• Using pm.environment.get() to set variables
• Not parsing JSON before accessing properties

3. Given the response body:

{"token": "abc123", "user": {"id": 42}}

What will this Postman script save in the environment variable authToken?

let jsonData = pm.response.json();
pm.environment.set('authToken', jsonData.token);

medium

A. null

B. 42

C. undefined

D. "abc123"

Solution

1. Step 1: Parse the JSON response

   jsonData.token accesses the 'token' key which has value "abc123".

2. Step 2: Set environment variable with token value

   pm.environment.set saves "abc123" as 'authToken'.

3. Final Answer:

   "abc123" -> Option D

4. Quick Check:

   jsonData.token = "abc123" [OK]

Hint: Access exact key from parsed JSON to get value [OK]

Common Mistakes:

• Using user.id instead of token
• Expecting number 42 instead of string token
• Not parsing JSON before accessing token

4. You wrote this Postman test script to extract sessionId from the response:

let data = pm.response.json();
pm.environment.set('sessionId', data.session_id);

But the environment variable sessionId is always empty. What is the likely problem?

medium

A. pm.response.json() does not parse JSON

B. pm.environment.set() cannot save variables

C. The response JSON uses sessionId not session_id

D. You must use pm.collectionVariables.set() instead

Solution

1. Step 1: Check JSON key names carefully

   The script uses 'session_id' but the response likely has 'sessionId' (camelCase).

2. Step 2: Correct key name to match response

   Use data.sessionId to correctly extract the value.

3. Final Answer:

   The response JSON uses sessionId not session_id -> Option C

4. Quick Check:

   Key name mismatch causes empty variable [OK]

Hint: Match JSON keys exactly, including case [OK]

Common Mistakes:

• Assuming pm.environment.set() doesn't work
• Not parsing JSON before accessing keys
• Confusing environment and collection variables

5. You receive this nested JSON response:

{"data": {"users": [{"id": 1, "name": "Alice"}, {"id": 2, "name": "Bob"}]}}

How do you extract and save the name of the second user as a collection variable in Postman?

hard

A. pm.environment.set('secondUserName', pm.response.json().data.users[1].name);

B. let json = pm.response.json(); pm.collectionVariables.set('secondUserName', json.data.users[1].name);

C. let json = pm.response.json(); pm.environment.set('secondUserName', json.data.users[2].name);

D. pm.collectionVariables.set('secondUserName', pm.response.json().users[2].name);

Solution

1. Step 1: Parse the nested JSON response

   Access the array at json.data.users and select index 1 for the second user.

2. Step 2: Save the second user's name as a collection variable

   Use pm.collectionVariables.set with key 'secondUserName' and value json.data.users[1].name.

3. Final Answer:

   let json = pm.response.json(); pm.collectionVariables.set('secondUserName', json.data.users[1].name); -> Option B

4. Quick Check:

   Index 1 in users array = second user name [OK]

Hint: Use zero-based index and correct variable scope [OK]

Common Mistakes:

• Using index 2 instead of 1 for second user
• Mixing environment and collection variables
• Not parsing JSON before accessing nested data